Decoding genetic and pathophysiological mechanisms in amyotrophic lateral sclerosis and primary lateral sclerosis: A comparative study of differentially expressed genes and implicated pathways in motor neuron disorders.

Motor Neuron Disorders (MNDs), characterized by the degradation and loss of function of motor neurons, are recognized as fatal conditions with limited treatment options and no known cure. The present study aimed to identify the pathophysiological functions and affected genes in patients with MNDs, specifically Amyotrophic Lateral Sclerosis (ALS) and Primary Lateral Sclerosis (PLS). The GSE56808 dataset comprised three sample groups: six patients diagnosed with ALS (GSM1369650, GSM1369652, GSM1369654, GSM1369656, GSM1369657, GSM1369658), five patients diagnosed with PLS (GSM1369648, GSM1369649, GSM1369653, GSM1369655, GSM1369659), and six normal controls (GSM1369642, GSM1369643, GSM1369644, GSM1369645, GSM1369646, and GSM1369647). The application of computational analysis of microarray gene expression profiles enabled us to identify 346 significantly differentially expressed genes (DEGs), 169 genes for the ALS sample study, and 177 genes for the PLS sample study. Enrichment was carried out using MCODE, a Cytoscape plugin. Functional annotation of DEGs was carried out via ClueGO/CluePedia (v2.5.9) and further validated via the DAVID database. NRP2, SEMA3D, ROBO3 and, CACNB1, CACNG2 genes were identified as the gene of interest for ALS and PLS sample groups, respectively. Axonal guidance (GO:0007411) and calcium ion transmembrane transport (GO:0070588) were identified to be some of the significantly dysregulated gene ontology (GO) terms, with arrhythmogenic right ventricular cardiomyopathy (KEGG:05412) to be the top relevant KEGG pathway which is affected in MND patients. ROBO3 gene was observed to have distinctive roles in ALS and PLS-affected patients, hinting towards the differential progression of ALS from PLS. The insights derived from our comprehensive analysis accentuate the distinct variances in the underlying molecular pathogenesis of ALS and PLS. Further research should investigate the mechanistic roles of the identified DEGs and molecular pathways, leading to potential targeted therapies for ALS and PLS.

Upper motor neuron-predominant motor neuron disease presenting as atypical parkinsonism: A clinicopathological study.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by upper and lower motor neuron signs. There are, however, cases where upper motor neurons (UMNs) are predominantly affected, leading to clinical presentations of UMN-dominant ALS or primary lateral sclerosis. Furthermore, cases exhibiting an UMN-predominant pattern of motor neuron disease (MND) presenting with corticobasal syndrome (CBS) have been sparsely reported. This study aims to clarify the clinicopathological features of patients with UMN-predominant MND. We reviewed 24 patients with UMN-predominant MND with TDP-43 pathology in the presence or absence of frontotemporal lobar degeneration. Additionally, we reviewed the medical records of patients with pathologically-confirmed corticobasal degeneration (CBD) who received a final clinical diagnosis of CBS (n = 10) and patients with pathologically-confirmed progressive supranuclear palsy (PSP) who received a final clinical diagnosis of PSP syndrome (n = 10). Of 24 UMN-predominant MND patients, 20 had a clinical diagnosis of an atypical parkinsonian disorder, including CBS (n = 11) and PSP syndrome (n = 8). Only two patients had antemortem diagnoses of motor neuron disease. UMN-predominant MND patients with CBS less frequently exhibited apraxia than those with CBD, and they were less likely to meet clinical criteria for possible or probable CBS. Similarly, UMN-predominant MND patients with PSP syndrome less often met clinical criteria for probable PSP than PSP patients with PSP syndrome. Our findings suggest that UMN-predominant MND can mimic atypical parkinsonism, and should be considered in the differential diagnosis of CBS and PSP syndrome, in particular when criteria are not met.

F wave analysis based on the compound muscle action potential scan.

INTRODUCTION/AIMS: Conventional F wave analysis involves a relatively uniform physiological environment induced by supramaximal stimulations. The F wave characteristics in a dynamic physiological condition, however, are rarely investigated. This study aimed to improve understanding of F wave properties in the more dynamic process by introducing a novel method to analyze F waves based on the compound muscle action potential (CMAP) scan technique. METHODS: Twenty four healthy subjects participated in the study. The CMAP scan was applied to record muscle responses in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles, respectively. F wave characteristics including mean F wave amplitude and latency (F-M latency), persistence and activating threshold were quantified. RESULTS: An average of 200 F waves per muscle were obtained from the CMAP scan recording. Weak to moderate correlations between F wave amplitude and stimulating intensity were observed in most of the APB (19 muscles; r = 0.33 ± 0.14, all p < .05) and ADM (23 muscles, r = 0.46 ± 0.16, all p < .05) muscles. Significantly longer mean F latency and lower activating F-threshold were found in the ADM muscles (F-M latency: APB: 25.43 ± 2.39 ms, ADM: 26.15 ± 2.32 ms, p < .05; F-threshold: APB: 7.68 ± 8.96% CMAP, ADM: 2.35 ± 2.42% CMAP, p < .05). DISCUSSION: This study introduces new features of F waves using the CMAP scan technique and identifies differences of F wave characteristics between the hand muscles. The CMAP scan based F waves analysis can be combined with the motor unit number estimation to assess functional alterations in motor neurons in neurological disorders.

Autonomic Dysfunction in Amyotrophic Lateral Sclerosis - A Case-Control Study.

INTRODUCTION: This study aimed to explore autonomic nervous system involvement in amyotrophic lateral sclerosis (ALS) patients by evaluating sympathetic skin response (SSR). MATERIALS AND METHODS: The study included 35 sporadic (ALS) patients (cases), and 35 healthy age and sex-matched participants (controls) aged <60 years. SSR was recorded in the electrophysiology lab of the Neurology Department of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Patients with diseases associated with peripheral or autonomic neuropathy were excluded. Prolonged latency (delayed SSR) or an absent response was considered abnormal SSR. RESULTS: SSR was found to be abnormal in 17 (48.6 %) ALS cases, with an absent response in the upper limbs of six cases (17.1%). Abnormal SSR was more prevalent in the lower limbs, with 33 (94.3%) and 20 (57.1%) cases having a delayed or absent response, respectively. In comparison, SSR was normal in all control participants (P-value <0.05). Abnormal SSR was significantly more common in the lower limbs of ALS cases with bulbar palsy than those without bulbar palsy (P-value=0.04). There was no association of SSR with disease severity and duration. CONCLUSION: ALS is significantly associated with abnormal SSR, indicating autonomic nervous system involvement. There could also be an association between bulbar palsy and abnormal SSR among ALS patients. Further studies should be carried out to determine the association of abnormal SSR with disease severity, duration, and type.

Patients' and caregivers' perception of multidimensional and palliative care in amyotrophic lateral sclerosis - protocol of a German multicentre study.

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is an inevitably fatal condition that leads to a progressive loss of physical functioning, which results in a high psychosocial burden and organizational challenges related to medical care. Multidimensional and multiprofessional care is advised to meet the complex needs of patients and their families. Many healthcare systems, including Germany, may not be able to meet these needs because non-medical services such as psychological support or social counselling are not regularly included in the care of patients with ALS (pwALS). Specialised neuropalliative care is not routinely implemented nor widely available. Caregivers of pwALS are also highly burdened, but there is still a lack of support services for them. METHODS: This project aims to assess the perceptions and satisfaction with ALS care in Germany in pwALS and their caregivers. This will be achieved by means of a cross-sectional, multicentre survey. The examination will assess, to which extend the patients' needs in the six domains of physical, psychological, social, spiritual, practical and informational are being met by current care structures. This assessment will be linked to mental well-being, subjective quality of life, attitudes toward life-sustaining measures and physician-assisted suicide, and caregiver burden. The study aims to recruit 500 participants from nationwide ALS centres in order to draw comprehensive conclusions for Germany. A total of 29 centres, mostly acquired via the clinical and scientific German Network for Motor Neuron Diseases (MND-NET), will take part in the project, 25 of which have already started recruitment. PERSPECTIVE: It is intended to provide data-based starting points on how current practice of care in Germany is perceived pwALS and their caregivers and how it can be improved according to their needs. Planning and initiation of the study has been completed. TRIAL REGISTRATION: The study is registered at ClinicalTrails.gov; NCT06418646.

Diving deep: zebrafish models in motor neuron degeneration research.

In the dynamic landscape of biomedical science, the pursuit of effective treatments for motor neuron disorders like hereditary spastic paraplegia (HSP), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA) remains a key priority. Central to this endeavor is the development of robust animal models, with the zebrafish emerging as a prime candidate. Exhibiting embryonic transparency, a swift life cycle, and significant genetic and neuroanatomical congruencies with humans, zebrafish offer substantial potential for research. Despite the difference in locomotion-zebrafish undulate while humans use limbs, the zebrafish presents relevant phenotypic parallels to human motor control disorders, providing valuable insights into neurodegenerative diseases. This review explores the zebrafish's inherent traits and how they facilitate profound insights into the complex behavioral and cellular phenotypes associated with these disorders. Furthermore, we examine recent advancements in high-throughput drug screening using the zebrafish model, a promising avenue for identifying therapeutically potent compounds.

New opportunities for antioxidants in amelioration of neurodegenerative diseases.

This comprehensive review elucidates the critical role of antioxidants to mitigate oxidative stress, a common denominator in an array of neurodegenerative disorders. Oxidative stress-induced damage has been linked to the development of diseases such as Alzheimer's, Parkinson's, Huntington's disease and amyotrophic lateral sclerosis. This article examines a wide range of scientific literature and methodically delineates the several methods by which antioxidants exercise their neuroprotective benefits. It also explores into the complex relationship between oxidative stress and neuroinflammation, focusing on how antioxidants can alter signaling pathways and transcription factors to slow neurodegenerative processes. Key antioxidants, such as vitamins C and E, glutathione, and polyphenolic compounds, are tested for their ability to combat reactive oxygen and nitrogen species. The dual character of antioxidants, which operate as both direct free radical scavengers and regulators of cellular redox homeostasis, is investigated in terms of therapeutic potential. Furthermore, the study focuses on new antioxidant-based therapy techniques and their mechanisms including Nrf-2, PCG1α, Thioredoxin etc., which range from dietary interventions to targeted antioxidant molecules. Insights into ongoing clinical studies evaluating antioxidant therapies in neurodegenerative illnesses offer an insight into the translational potential of antioxidant research. Finally, this review summarizes our present understanding of antioxidant processes in neurodegenerative illnesses, providing important possibilities for future study and treatment development.

Identification of a pathogenic mutation in ARPP21 in patients with amyotrophic lateral sclerosis.

BACKGROUND AND OBJECTIVE: Between 5% and 10% of amyotrophic lateral sclerosis (ALS) cases have a family history of the disease, 30% of which do not have an identifiable underlying genetic cause after a comprehensive study of the known ALS-related genes. Based on a significantly increased incidence of ALS in a small geographical region from Spain, the aim of this work was to identify novel ALS-related genes in ALS cases with negative genetic testing. METHODS: We detected an increased incidence of both sporadic and, especially, familial ALS cases in a small region from Spain compared with available demographic and epidemiological data. We performed whole genome sequencing in a group of 12 patients with ALS (5 of them familial) from this unique area. We expanded the study to include affected family members and additional cases from a wider surrounding region. RESULTS: We identified a shared missense mutation (c.1586C>T; p.Pro529Leu) in the cyclic AMP regulated phosphoprotein 21 (ARPP21) gene that encodes an RNA-binding protein, in a total of 10 patients with ALS from 7 unrelated families. No mutations were found in other ALS-causing genes. CONCLUSIONS: While previous studies have dismissed a causal role of ARPP21 in ALS, our results strongly support ARPP21 as a novel ALS-causing gene.

Adolescents' challenging and grief-filled transitions when living with a parent with ALS: A qualitative interpretive study.

OBJECTIVE: The study aimed to explore the meaning for adolescents of living with a parent with amyotrophic lateral sclerosis (ALS). METHODS: The design is qualitative. Interviews were conducted between December 2020 and April 2022 with 11 adolescents (8-25 y), living in households with a parent with ALS in Sweden. The analysis was phenomenologically hermeneutical. RESULTS: The adolescents were in a difficult and exposed situation, especially if the parent had a severe disability and assistant care providers were in the home. Witnessing the gradual loss of the parent in an indefinite battle against time, while still needing them, elicited grief-filled and hard-to-manage emotions. Everyday life was turned upside down, resulting in greater responsibility for the adolescents, not only in helping with household chores and assisting the ill parent, but also in emotionally protecting both parents. It forced the adolescents to mature faster and put their own life on hold, triggering experiences of being limited. This, together with changing family roles yet being more attached to home, reinforced the imbalance in the adolescents' lives. The interpreted whole of the adolescents' narratives revealed that living with a parent with ALS meant a challenging and grieving transition during an already transition-filled adolescence, which left the adolescents struggling to keep a foothold on a life torn apart. CONCLUSION: The unbalanced life situation may hinder the adolescents' identity formation and emancipation, which are developmentally important for managing a healthy and independent adulthood. The results emphasize the importance of early targeted support to reach this vulnerable group in order to secure their health.

Amyotrophic lateral sclerosis patients with various gene mutations show diverse motor phenotypes and survival in China.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterised by progressive degeneration of motor neurons. Genetic factors have a substantial impact on ALS. Therefore, this study aimed to explore the correlation between genotype (SOD1, TARDBP, FUS, C9orf72) and phenotype in ALS. METHODS: Genetic analysis was performed on 2038 patients with ALS, among which 1696 patients with sporadic ALS (SALS) as controls for genotype-phenotype analysis, and 1602 SALS as controls for survival analysis. Logistic regression and Cox proportional hazards models were used for statistical analysis. RESULTS: A total of 172 patients with ALS with the gene mutations were included in the statistical analysis (SOD1, n=65; FUS, n=43; TARDBP, n=27; C9orf72, n=37). SOD1 mutations were more frequent in flail leg phenotype (OR 7.317, p=0.001) and less in bulbar phenotype (OR 0.222, p=0.038). C9orf72 expansions exhibited higher frequency in bulbar phenotype (OR 2.770, p=0.008). SOD1 and FUS mutations were significantly associated with earlier age of onset (HR 2.039, p<0.001; HR 1.762, p=0.001). The patients with SOD1 mutations, C9orf72 expansions and those carrying pathogenic FUS mutations had significantly increased death risk (HR 2.217, p<0.001; HR 1.694, p=0.008; HR 1.652, p=0.036). The increased risk of death in ALS with C9orf72 expansions was significant in females (HR 2.419, p=0.014) but not in males (HR 1.442, p=0.128). CONCLUSION: Our study revealed distinct motor phenotypic tendencies in patients with ALS with different genotypes, indicating variations in the vulnerability of motor neurons during the disease's progression. Furthermore, we made novel discoveries regarding survival of different gene mutations, warranting further investigation.

Autophagy markers LC3 and p62 in aging lumbar motor neurons.

Autophagy is a ubiquitous process through which damaged cytoplasmic structures are recycled and degraded within cells. Aging can affect autophagy regulation in different steps leading to the accumulation of damaged organelles and proteins, which can contribute to cell dysfunction and death. Motor neuron (MN) loss and sarcopenia are prominent features of neuromuscular aging. Previous studies on phrenic MNs showed increased levels of the autophagy proteins LC3 and p62 in 24 month compared to 6 month old mice, consistent with the onset of diaphragm muscle sarcopenia. In the present study, we hypothesized that aging leads to increased expression of the autophagy markers LC3 and p62 in single lumbar MNs. Expression of LC3 and p62 in lumbar MNs (spinal levels L1-L6) was assessed using immunofluorescence and confocal imaging of male and female mice at 6, 18 and 24 months of age, reflecting 100 %, 90 % and 75 % survival, respectively. A mixed linear model with animal as a random effect was used to compare relative LC3 and p62 expression in choline acetyl transferase-positive MNs across age groups. Expression of LC3 and p62 decreased in the white matter of the lumbar spinal cord with aging, with ~29 % decrease in LC3 and ~ 7 % decrease in p62 expression at 24 months of age compared to 6 months of age. There was no change in LC3 or p62 expression in the gray matter with age. LC3 expression in MNs relative to white matter increased significantly with age, with 150 % increase at 24 months of age compared to 6 months of age. Similarly, p62 expression in MNs relative to white matter increased significantly with age, with ~14 % increase at 24 months of age compared to 6 months of age. No effect of sex or MN pool was observed in LC3 and p62 expression in MNs. Overall, these data suggest autophagy impairment during elongation (increased LC3) and degradation (increased p62) phases with aging in lumbar MNs.

Chest Dynamic MRI as Early Biomarker of Respiratory Impairment in Amyotrophic Lateral Sclerosis Patients: A Pilot Study.

Background: Amyotrophic lateral sclerosis (ALS) is a neuromuscular progressive disorder characterized by limb and bulbar muscle wasting and weakness. A total of 30% of patients present a bulbar onset, while 70% have a spinal outbreak. Respiratory involvement represents one of the worst prognostic factors, and its early identification is fundamental for the early starting of non-invasive ventilation and for the stratification of patients. Due to the lack of biomarkers of early respiratory impairment, we aimed to evaluate the role of chest dynamic MRI in ALS patients. Methods: We enrolled 15 ALS patients and 11 healthy controls. We assessed the revised ALS functional rating scale, spirometry, and chest dynamic MRI. Data were analyzed by using the Mann-Whitney U test and Cox regression analysis. Results: We observed a statistically significant difference in both respiratory parameters and pulmonary measurements at MRI between ALS patients and healthy controls. Moreover, we found a close relationship between pulmonary measurements at MRI and respiratory parameters, which was statistically significant after multivariate analysis. A sub-group analysis including ALS patients without respiratory symptoms and with normal spirometry values revealed the superiority of chest dynamic MRI measurements in detecting signs of early respiratory impairment. Conclusions: Our data suggest the usefulness of chest dynamic MRI, a fast and economically affordable examination, in the evaluation of early respiratory impairment in ALS patients.

Genotypes and phenotypes of motor neuron disease: an update of the genetic landscape in Scotland.

BACKGROUND: Using the Clinical Audit Research and Evaluation of Motor Neuron Disease (CARE-MND) database and the Scottish Regenerative Neurology Tissue Bank, we aimed to outline the genetic epidemiology and phenotypes of an incident cohort of people with MND (pwMND) to gain a realistic impression of the genetic landscape and genotype-phenotype associations. METHODS: Phenotypic markers were identified from the CARE-MND platform. Sequence analysis of 48 genes was undertaken. Variants were classified using a structured evidence-based approach. Samples were also tested for C9orf72 hexanucleotide expansions using repeat-prime PCR methodology. RESULTS: 339 pwMND donated a DNA sample: 44 (13.0%) fulfilled criteria for having a pathogenic variant/repeat expansion, 53.5% of those with a family history of MND and 9.3% of those without. The majority (30 (8.8%)) had a pathogenic C9orf72 repeat expansion, including two with intermediate expansions. Having a C9orf72 expansion was associated with a significantly lower Edinburgh Cognitive and Behavioural ALS Screen ALS-Specific score (p = 0.0005). The known pathogenic SOD1 variant p.(Ile114Thr), frequently observed in the Scottish population, was detected in 9 (2.7%) of total cases but in 17.9% of familial cases. Rare variants were detected in FUS and NEK1. One individual carried both a C9orf72 expansion and SOD1 variant. CONCLUSIONS: Our results provide an accurate summary of MND demographics and genetic epidemiology. We recommend early genetic testing of people with cognitive impairment to ensure that C9orf72 carriers are given the best opportunity for informed treatment planning. Scotland is enriched for the SOD1 p.(Ile114Thr) variant and this has significant implications with regards to future genetically-targeted treatments.

Genome Editing Approaches Using Zinc Finger Nucleases (ZFNs) for the Treatment of Motor Neuron Diseases.

Motor neuron disorders are diseases that can be passed through generations by heredity or they occur due to spontaneous mutations in the gene. These are the disorders that weaken the connection between motor neurons and the muscles, due to this the coordination between the neurons and muscles gets disturbed and thereby the actions become abnormal, every year millions of people around the world suffer from these different types of motor neuron disorders. Till now there is no proper known treatment for this type of disorder, there is active research work going on to treat these diseases permanently. Some gene therapy treatments are giving promising results in the treatment of these diseases, specifically, genetic modification techniques are the front liners, and many types of nucleases are doing their work to replace the mutated gene with a functional one. Zinc finger nucleases (ZFNs) are one of them with good disease treatment potential with accurate and desirable effects. In this review, we note the complete information about ZFNs and their drawbacks along with their future prospective in gene therapy and also shortly with other types of nucleases-mediated gene therapies. There also some factors that influence the gene therapy treatment are also noted along with some detailed information.

An Insightful Observation Leading to a Late Diagnosis of Spinal Muscular Atrophy: A Case Report.

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disorder characterized by the loss of motor neurons in the spinal cord that results in progressive muscle weakness and atrophy. Most often, the gene involved in this disorder is the survival motor neuron (SMN1) gene, located on the telomeric regions of chromosome 5q13. This gene is involved in the processing of pre-mRNA required for the formation of dendrites and axons. Here we present the case of a 47-year-old female with an extensive past medical history of progressive muscle weakness who, after numerous specialist evaluations, was sent for germline mutation panel sequencing and analysis and was incidentally found to have a pathogenic heterozygous deletion encompassing the exon 8 region of the SMN1 gene. This case report aims to highlight the importance of timely identification and management for individuals who present with early clinical signs of the disease to reduce the morbidity and mortality associated with it.

A Presentation of Meige Syndrome With Associated Upper Motor Neuron Symptoms.

Meige syndrome (MS) is a cranial dystonia that involves blepharospasm and oromandibular dystonia. It can also evolve to include other adjacent muscle groups in the cervical region. It typically presents in middle-aged females, and while the disorder is relatively uncommon, its exact prevalence varies. Diagnosis is typically made with a thorough history and physical and workup to rule out other causes. Treatment options include medical management with gamma-aminobutyric acid (GABA) antagonists, dopamine antagonists, and anticholinergics for short-term management. Long-term treatment options are Botox and deep brain stimulation. This case report presents a 56-year-old female with a complex presentation of MS; the patient's symptoms progressed from isolated blepharospasms to involve orofacial and cervical musculature. A distinctive aspect of this case was the simultaneous presence of upper motor neuron (UMN) signs in the patient alongside acute to subacute compression fractures of the superior endplate of C7 and T3, as revealed by cervical spine imaging. Treatment with clonazepam led to significant symptomatic improvement, highlighting the importance of a multimodal approach in managing MS. This case underscores the need for careful clinical evaluation, collaboration with movement disorder specialists, and ongoing research efforts to enhance understanding and treatment of MS.

[LIU Zhishun's clinical experience of electroacupuncture for pediatric neurogenic bladder of lower motor neuron type in children].

Professor LIU Zhishun's clinical experience of electroacupuncture (EA) for pediatric neurogenic bladder of lower motor neuron type in children is summarized. Considering the unique physiological and pathological characteristics of children, with the strategy of combining "disease-symptom-location" in the selection of acupoints, professor LIU Zhishun proposes that the main disease location is the bladder and kidney, with the involvement of the conception vessel, governor vessel, kidney meridian of foot-shaoyin and the bladder meridian of foot-taiyang. The primary acupoint prescription-1 (bilateral Zhongliao [BL 33], Ciliao [BL 32] and Huiyang [BL 35]) and primary acupoint prescription-2 (Guanyuan [CV 4], Zhongji [CV 3] and bilateral Sanyinjiao [SP 6]) are selected to promote the yang of the governor vessel, stimulate the yin of the conception vessel, and invigorate the bladder's qi transformation. Before acupuncture, the four-step method is applied to precisely locate Ciliao (BL 32) and Zhongliao (BL 33). During acupuncture, the importance of achieving deqi is emphasized, with deep insertion in the sacral area to reach the disease location. Based on the tolerance characteristics of children, low-frequency EA and gentle moxibustion treatment are applied.

Analysis and occurrence of biallelic pathogenic repeat expansions in RFC1 in a German cohort of patients with a main clinical phenotype of motor neuron disease.

Biallelic pathogenic repeat expansions in RFC1 were recently identified as molecular origin of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) as well as of one of the most common causes of adult-onset ataxia. In the meantime, the phenotypic spectrum has expanded massively and now includes mimics of multiple system atrophy or parkinsonism. After identifying a patient with a clinical diagnosis of amyotrophic lateral sclerosis (ALS) as a carrier of biallelic pathogenic repeat expansions in RFC1, we studied a cohort of 106 additional patients with a clinical main phenotype of motor neuron disease (MND) to analyze whether such repeat expansions are more common in MND patients. Indeed, two additional MND patients (one also with ALS and one with primary lateral sclerosis/PLS) have been identified as carrier of biallelic pathogenic repeat expansions in RFC1 in the absence of another genetic alteration explaining the phenotype, suggesting motor neuron disease as another extreme phenotype of RFC1 spectrum disorder. Therefore, MND might belong to the expanding phenotypic spectrum of pathogenic RFC1 repeat expansions, particularly in those MND patients with additional features such as sensory and/or autonomic neuropathy, vestibular deficits, or cerebellar signs. By systematically analyzing the RFC1 repeat array using Oxford nanopore technology long-read sequencing, our study highlights the high intra- and interallelic heterogeneity of this locus and allows the identification of the novel repeat motif 'ACAAG'.

Elevated NLRP3 Inflammasome Activation Is Associated with Motor Neuron Degeneration in ALS.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron degeneration in the central nervous system. Recent research has increasingly linked the activation of nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome to ALS pathogenesis. NLRP3 activation triggers Caspase 1 (CASP 1) auto-activation, leading to the cleavage of Gasdermin D (GSDMD) and pore formation on the cellular membrane. This process facilitates cytokine secretion and ultimately results in pyroptotic cell death, highlighting the complex interplay of inflammation and neurodegeneration in ALS. This study aimed to characterize the NLRP3 inflammasome components and their colocalization with cellular markers using the wobbler mouse as an ALS animal model. Firstly, we checked the levels of miR-223-3p because of its association with NLRP3 inflammasome activity. The wobbler mice showed an increased expression of miR-223-3p in the ventral horn, spinal cord, and cerebellum tissues. Next, increased levels of NLRP3, pro-CASP 1, cleaved CASP 1 (c-CASP 1), full-length GSDMD, and cleaved GDSMD revealed NLRP3 inflammasome activation in wobbler spinal cords, but not in the cerebellum. Furthermore, we investigated the colocalization of the aforementioned proteins with neurons, microglia, and astrocyte markers in the spinal cord tissue. Evidently, the wobbler mice displayed microgliosis, astrogliosis, and motor neuron degeneration in this tissue. Additionally, we showed the upregulation of protein levels and the colocalization of NLRP3, c-CASP1, and GSDMD in neurons, as well as in microglia and astrocytes. Overall, this study demonstrated the involvement of NLRP3 inflammasome activation and pyroptotic cell death in the spinal cord tissue of wobbler mice, which could further exacerbate the motor neuron degeneration and neuroinflammation in this ALS mouse model.

Multicenter expanded access program for access to investigational products for amyotrophic lateral sclerosis.

INTRODUCTION/AIMS: Expanded access (EA) is a Food and Drug Administration-regulated pathway to provide access to investigational products (IPs) to individuals with serious diseases who are ineligible for clinical trials. The aim of this report is to share the design and operations of a multicenter, multidrug EA program for amyotrophic lateral sclerosis (ALS) across nine US centers. METHODS: A central coordination center was established to design and conduct the program. Templated documents and processes were developed to streamline study design, regulatory submissions, and clinical operations across protocols. The program included three protocols and provided access to IPs that were being tested in respective regimens of the HEALEY ALS Platform Trial (verdiperstat, CNM-Au8, and pridopidine). Clinical and safety data were collected in all EA protocols (EAPs). The program cohorts comprised participants who were not eligible for the platform trial, including participants at advanced stages of disease progression and with long disease duration. RESULTS: A total of 85 participants were screened across the 3 EAPs from July 2021 to September 2022. The screen failure rate was 3.5%. Enrollment for the regimens of the platform trial was completed as planned and results informed the duration of the corresponding EAP. The verdiperstat EAP was concluded in December 2022. Mean duration of participation in the verdiperstat EAP was 5.8 ± 4.1 months. The CNM-Au8 and pridopidine EAPs are ongoing. DISCUSSION: Multicenter EAPs conducted in parallel to randomized clinical trials for ALS can successfully enroll participants who do not qualify for clinical trials.